The tool needed:
A can you like
A paper clip
A clock mechanism
Less than $15
Clock mechanism is $9 with hands, without shipping form clockparts.com, the can and the whisk are not so expensive.
How to make it:
Open then from one side, just half the way to let the pendulum move freely.
Using the drill, gently make a hole to let the shaft of the pendulum go through. The mechanism come with a nut that will maintain the mechanism attached to the can.
To attach the whisk to the pendulum mechanism, a piece of wire such as a paper clip will do it.
You can make a hole on the back of your clock to hang it to a nail.
It's an easy project that will allow many variation in style, I will post plenty of them in the next weeks.